In a computerized content delivery network, first-party content providers can provide information for public presentation of resources, such as web pages, documents, applications, and/or other resources. Additional third-party content can also be provided by third-party content providers for presentation on the user device together with the first-party content provided by the first-party content providers. Thus, a user viewing a resource can access the first-party content that is the subject of the resource as well as the third-party content that may or may not be related to the subject matter of the resource.
A third-party content provider may provide an identifier to be presented along with a third-party content item. A user viewing the third-party content item may also view or access the identifier. The user may be able to use the identifier to contact the third-party content provider.